部署Django应用至DigitalOcean时遇ModuleNotFoundError问题求助

问题描述 #

通过wsgi.py和Dockerfile部署Django应用到DigitalOcean，构建成功但部署阶段报错，提示ModuleNotFoundError: No module named 'users'。使用manage.py startapp创建了users和documents应用，推测是路径配置问题导致INSTALLED_APPS中的应用无法被识别。

错误日志 #

[2022-07-31 05:49:23]   File "/code/scraft-server/wsgi.py", line 14, in <module>
[2022-07-31 05:49:23]     from configurations.wsgi import get_wsgi_application  # noqa
[2022-07-31 05:49:23]   File "/usr/local/lib/python3.8/site-packages/configurations/wsgi.py", line 8, in <module>
[2022-07-31 05:49:23]     application = get_wsgi_application()
[2022-07-31 05:49:23]   File "/usr/local/lib/python3.8/site-packages/django/core/wsgi.py", line 12, in get_wsgi_application
[2022-07-31 05:49:23]     django.setup(set_prefix=False)
[2022-07-31 05:49:23]   File "/usr/local/lib/python3.8/site-packages/django/__init__.py", line 24, in setup
[2022-07-31 05:49:23]     apps.populate(settings.INSTALLED_APPS)
[2022-07-31 05:49:23]   File "/usr/local/lib/python3.8/site-packages/django/apps/registry.py", line 91, in populate
[2022-07-31 05:49:23]     app_config = AppConfig.create(entry)
[2022-07-31 05:49:23]   File "/usr/local/lib/python3.8/site-packages/django/apps/config.py", line 223, in create
[2022-07-31 05:49:23]     import_module(entry)
[2022-07-31 05:49:23]   File "/usr/local/lib/python3.8/importlib/__init__.py", line 127, in import_module
[2022-07-31 05:49:23]     return _bootstrap._gcd_import(name[level:], package, level)
[2022-07-31 05:49:23] ModuleNotFoundError: No module named 'users'

文件目录结构 #

monorepo
├── README.md
├── __init__.py
├── backend-server
│	├── users //(created with startapp)
│	├── documents //(created with startapp)
│	├── config
│	│	├── common.py
│	│	├── local.py
│	│	├── production.py
│	├── ...
├── docker-compose.yml
├── manage.py
├── requirements.txt
├── users
├── urls.py
├── wait_for_postgres.py
└── wsgi.py

相关文件代码 #

wsgi.py #

import os

from configurations.wsgi import get_wsgi_application  # noqa

application = get_wsgi_application()

config.production.py #

import os
from .common import Common

class Production(Common):
    INSTALLED_APPS = (
        # ...
        # My apps
        "users",
        "document",
        # etc
        "corsheaders",
        "gunicorn",
    )
    SECRET_KEY = os.getenv("DJANGO_SECRET_KEY")
    # all other configs are set inside config.common.py

DockerFile #

FROM python:3.8
ENV PYTHONUNBUFFERED 1
ENV DJANGO_SETTINGS_MODULE backend-server.config.production
ENV DJANGO_CONFIGURATION Production

# Allows docker to cache installed dependencies between builds
COPY ./requirements.txt requirements.txt
RUN pip install -r requirements.txt

# Adds our application code to the image
WORKDIR /code/backend-server
COPY backend-server .  
WORKDIR /code

EXPOSE 8000

# Run the production server
CMD newrelic-admin run-program gunicorn --bind localhost:$PORT --access-logfile - backend-server.wsgi:application

问题根源 #

1. INSTALLED_APPS路径错误：users和documents应用属于backend-server包的子模块，但配置中直接写"users"、"document"（还存在拼写错误，应为documents），导致Django无法定位模块。
2. 冗余目录干扰：根目录下存在空的users目录，可能造成路径识别混淆。

修复步骤 #

1. 修正INSTALLED_APPS配置 #

修改config/production.py，将应用改为完整的包路径，同时修正拼写错误：

class Production(Common):
    INSTALLED_APPS = (
        # ... 保留原有第三方应用
        # 替换为完整包路径
        "backend-server.users",
        "backend-server.documents",
        "corsheaders",
        "gunicorn",
    )
    # ... 其他配置不变

2. 确保backend-server为有效Python包 #

检查backend-server目录下是否存在__init__.py文件（空文件即可），如果没有则创建，确保Python能识别该目录为可导入包。

3. 删除冗余目录 #

删除根目录下的空users目录，避免路径混淆：

rm -rf ./users

4. 验证Docker配置 #

当前Dockerfile的路径配置是正确的：将backend-server内容复制到/code/backend-server，工作目录设为/code，而/code会被加入Python的sys.path，Django可以正常识别backend-server包。

验证修复 #

重新构建镜像并部署，若仍有问题，可进入容器验证模块导入：

docker exec -it <容器ID> python
>>> import backend-server.users
>>> import backend-server.documents

无报错则说明路径配置正确。

内容的提问来源于stack exchange，提问作者Tyler Kim